1. Field of the Invention
The present invention relates to a method of retrieving underground cable or removing cable from conduit and more particularly, multi-conductor cable, such as telecommunication cable.
2. Description of Prior Art
During the installation process, a telecommunications cable is pressurized with air as a measure of protection. The pressurization of this cable and the settlement of the earth around it or the filling of the conduit with mud over a period of time creates friction between the cable and its surroundings which makes it difficult to remove. When the underground telecommunication cable or the cable routed in conduit is no longer in service, for example, when a communication system is being expanded when a more advanced system, such as a fiber optic system, is installed, the previous service cable is abandoned underground or within the conduit because of the cost involved in removing it.
There are methods known for removing underground cables. However, no methods currently in use incorporate the collapse of the cable or the reduction of the diameter of the cable through an evacuation process.
U.S. Pat. No. 2,297,164 issued Sep. 29, 1942 to John E. Rainwater discloses an apparatus for pulling and replacing pipes by means of a cable and a device attached to the cable whereby a pipe may be pulled and replaced.
U.S. Pat. No. 4,018,058 issued Apr. 19, 1977 to Heinrich Eichenseher et al. discloses a method of recovering non-ferrous metal conductors from a sheathed cable laid in the earth which includes excavating the earth at intervals, severing the cables, and withdrawing the cable with the aid of a pulling force.
U.S. Pat. No. 4,685,831 issued Aug. 11, 1987 to Robert L. Mahoney discloses a cable removing apparatus and a method utilizing the apparatus to remove continuous lengths of underground cable.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.